Fast-growing trees are desirable for many landscapers and home gardeners who want a tree that will quickly provide shade, or who want to create a privacy screen or wind break. Unfortunately, that fast growth may come with a few downfalls. Many fast-growing, large trees have weak wood that splits easily, or are highly susceptible to insect pests and diseases. Furthermore, the large size of such trees makes them difficult to treat with chemicals. Still, many people are drawn to these tall, stately trees.
The Leyland cypress (Cupressocyparis leylandii) is a fast-growing evergreen that can reach heights of between 70 and 100 feet. The tree has a pleasing, pyramidal shape and can grow at a rate of up to 4 feet per year, especially when young. The Leyland cypress grows best on rich, well-draining soil, although it can adapt to poorer soil conditions. It enjoys full sun or partial shade and can tolerate severe pruning, making this tree an excellent choice for hedges. Unfortunately, this tree is highly susceptible to a fungal disease that causes cankers to form on branches. The branches then die, causing the tree to become severely disfigured. Bagworms are also known to be a problem on Leyland cypress trees.
Pacific willows (Salix lucida) are fast-growing deciduous trees. These water-loving trees are often planted by streams to prevent erosion, and are the largest wild species in the Pacific Northwest. Salix lucida trees can quickly reach heights of over 60 feet. This tree, which thrives in full sunlight, is found up and down the west coast of North America from Alaska to northern California. In addition, Pacific willows are one of the few fast-growing, tall trees that are extremely hardy, with no reported serious insect pests or diseases.
Black cottonwoods (Populus balsamifera ssp. Trichocarpa) are members of the Populus family. The black cottonwood has tiny, black seeds surrounded by cottony fluff, which is where the tree came by its common name. The Populus group of trees is often simply grouped together as “poplar” trees, which are known for their fast growth. The black cottonwood is the tallest deciduous tree in the western part of North America. This fast-growing tree can reach heights of up to 200 feet, towering above many other trees in the forest.